Quantum Dot/Remote Phosphor Display System Improvements

ABSTRACT

A display system comprises light sources configured to emit first light with a first spectral power distribution; light regeneration layers configured to be stimulated by the first light and to convert at least a portion of the first light and recycled light into second light, the second light comprising (a) primary spectral components that correspond to primary colors and (b) secondary spectral components that do not correspond to the primary colors; and notch filter layers configured to receive a portion of the second light and to filter out the secondary spectral components from the portion of the second light. The portion of the second light can be directed to a viewer of the display system and configured to render images viewable to the viewer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.61/703,020 filed Sep. 19, 2012, hereby incorporated by reference in itsentirety.

TECHNOLOGY

The present invention relates generally to display techniques, and inparticular, to display techniques using light regeneration materials.

BACKGROUND

Color filter arrays in LCD and OLED displays are commonly produced byphotolithographic techniques, or printing techniques, as part of the LCDand OLED panel production process of the LCD or OLED.

Color filters in emissive displays such as LCD and OLED displaystypically consist of red, green and blue filters. The color filters arepatterned over the pixel array to allow the pixel elements to modulatethe emitted light by color instead of only by intensity. In operation, abroadband light source provides light to pixel elements, for example, inLCD display systems. Alternatively, broadband light is created by whiteOLED pixel elements in OLED display systems. A pixel element can varythe intensity of the broadband light transmitting out of the pixelelement. The intensity-modulated broadband light of each pixel elementcan be further color-filtered by overlaying color filter. Light is muchwasted by color filters because, for example, in order to produce redlight, green and blue light from the broadband light source would beblocked.

Additionally, since a typical display system comprises many passivelight filtering components, much (e.g., over 95%) of the light generatedby a light source in the display system is not only inefficiently wastedbut also converted into harmful heat which degrades the performance andlifetime of the display system.

Thus, engineering a display system with wide color gamut and highluminance has been recognized as a costly endeavor by many displaymanufactures. Because of a high number of relatively expensive optical,audio, electronic and mechanical components involved and the complexityin integrating all of them into a single system, the cost ofmanufacturing a decent display system is typically very high.

The approaches described in this section are approaches that could bepursued, but not necessarily approaches that have been previouslyconceived or pursued. Therefore, unless otherwise indicated, it shouldnot be assumed that any of the approaches described in this sectionqualify as prior art merely by virtue of their inclusion in thissection. Similarly, issues identified with respect to one or moreapproaches should not assume to have been recognized in any prior art onthe basis of this section, unless otherwise indicated.

BRIEF DESCRIPTION OF DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1A through FIG. 1C illustrate example display systemconfigurations;

FIG. 2A illustrates example transmittances versus wavelengths for colorfilters;

FIG. 2B and FIG. 2C illustrate example spectral power distributions;

FIG. 3A through FIG. 3C illustrate example display system configurationsrelating to notch filters;

FIG. 4A illustrates example transmittances versus wavelengths for notchfilters;

FIG. 4B illustrates an example light spectral power distribution withpresence of notch filters;

FIG. 5A through FIG. 5C illustrate example display system configurationsrelating to pass band filters;

FIG. 6 illustrates an example transmittance versus wavelengths for passband filters, in comparison with example light spectral powerdistributions of light sources and light regeneration materials;

FIG. 7A and FIG. 7B illustrate example light units;

FIG. 8 illustrates example light spectral power distributions one ormore sets of light sources;

FIG. 9A through FIG. 9D illustrate example pixel structures;

FIG. 10A through FIG. 10F illustrate additional example pixelstructures;

FIG. 11 illustrates an example of shaping a spectral power distributionfrom a narrow band laser source;

FIG. 12 illustrates an example configuration in which light regenerationsheets are stacked;

FIG. 13 illustrates an example color array panel comprising quantum dotor phosphor materials;

FIG. 14 illustrates example steps in constructing a color array panel;

FIG. 15 illustrates an example configuration of display logic in adisplay system; and

FIG. 16 illustrates an example hardware platform on which a computer ora computing device as described herein may be implemented.

DESCRIPTION OF EXAMPLE POSSIBLE EMBODIMENTS

Example possible embodiments, which relate to remote phosphor(RP)/quantum-dot (QD) based display improvement techniques, aredescribed herein. In the following description, for the purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of the present invention. It will be apparent,however, that the present invention may be practiced without thesespecific details. In other instances, well-known structures and devicesare not described in exhaustive detail, in order to avoid unnecessarilyoccluding, obscuring, or obfuscating the present invention.

Example embodiments are described herein according to the followingoutline:

1. GENERAL OVERVIEW

2. STRUCTURE OVERVIEW

3. NOTCH FILTERS

4. PASS BAND FILTERS

5. LIGHT SOURCES

6. PIXEL STRUCTURES

7. SHAPING SPECTRAL POWER DISTRIBUTIONS

8. COLOR ARRAY PANELS

9. LIGHT SOURCE CONTROL LOGIC

10. IMPLEMENTATION MECHANISMS—HARDWARE OVERVIEW

11. EQUIVALENTS, EXTENSIONS, ALTERNATIVES AND MISCELLANEOUS

1. General Overview

This overview presents a basic description of some aspects of a possibleembodiment of the present invention. It should be noted that thisoverview is not an extensive or exhaustive summary of aspects of thepossible embodiment. Moreover, it should be noted that this overview isnot intended to be understood as identifying any particularlysignificant aspects or elements of the possible embodiment, nor asdelineating any scope of the possible embodiment in particular, nor theinvention in general. This overview merely presents some concepts thatrelate to the example possible embodiment in a condensed and simplifiedformat, and should be understood as merely a conceptual prelude to amore detailed description of example possible embodiments that followsbelow.

In a display system, light that renders an image to a viewer travelsthrough many optical layers, modules, structures, components, etc., fromlight sources to the viewer, and constitutes only a portion of totallight output from the light sources. A significant portion of the totallight output fails to reach the viewer for a variety of reasons. In anexample, if a pixel is to represent a red pixel value in an image to berendered, light of non-red colors is rejected or absorbed for the pixel.In another example, if a pixel is to represent a relatively dark pixelvalue in an image to be rendered, much of light incident on a lightmodulation layer such as a liquid crystal cell of the pixel is notallowed to transmit through the light modulation layer, as the liquidcrystal cell is set to a relatively less transparent state based on therelatively dark pixel value.

Light regeneration materials can be disposed with a display system toincrease optical efficiencies of display systems, for example, asdescribed in as described in U.S. Provisional Application No.61/486,160, filed on May 13, 2011, entitled “TECHNIQUES FOR QUANTUMDOTS”; U.S. Provisional Application No. 61/486,166, filed on May 13,2011, entitled “TECHNIQUES FOR QUANTUM DOT ILLUMINATIONS”; U.S.Provisional Application No. 61/486,171, filed on May 13, 2011, entitled“QUANTUM DOT FOR DISPLAY PANELS,” the contents of which are herebyincorporated herein by reference for all purposes as if fully set forthherein.

A light regeneration layer can be stimulated not only by light fromlight sources but also recycled light. Shorter-wavelength light can beconverted by the light regeneration layer into longer-wavelength light.For example, at least a portion of UV or blue light rejected alongoptical paths from the light sources to the viewer can be recycled intogreen or red light, which may be able to transmit through green or redcolor filters and reach the viewer.

However, a spectral power distribution of the recycled light thatstimulates a light regeneration light is typically different from aspectral power distribution of light emitted by light sources. Forexample, the recycled light may contain relatively high amounts andlocal peaks of relatively low light wavelengths as compared with thelight emitted by the light sources. Thus, even though increasing theamount of usable light, light recycling also can produce light ofintermediate colors between primary colors of a display system.Consequently, even though maximum luminance for individual pixels may beincreased with light recycling, light perceived by a viewer from thosepixels contains the intermediate colors, which desaturate the primarycolors and negatively impact wide gamut display operations.

Under techniques as described herein, intermediate colors produced inpart by a light regeneration layer from recycled light can be removed bynotch filters disposed in front of (closer to a viewer) the lightregeneration layer. Notch filters can be configured to reject specificlight wavelengths associated with the intermediate colors.

Color shift (e.g., white light tinted with yellow, etc.) caused byrecycled light can be especially significant around central portions ofpoint spread functions of light emitters in display systems usingdirect-lit light sources. As used herein, the term “direct-lit” refersto light injection by light emitters (e.g., LEDs, etc.) in a directiondirectly or substantially directly to a viewer. Additionally,optionally, or alternatively, intermediate colors that are caused inpart by recycled light can be reduced or avoided by using pass bandfilters disposed behind (further from a viewer) a light regenerationlayer. Pass band filters, which include but are not limited only todichroic mirrors, can be configured to pass specific lightwavelengths—for example—associated with light sources. The presence ofpass band filters localizes light of the specific light wavelengths(e.g., UV light, blue light, associated with light sources, etc.) in aparticular light recycling region on one side of the pass band filters,and confines light of other wavelengths (e.g., green, red, notassociated with the light sources, etc.) on the other side of the passband filters. As a result, typical optical paths from the light sourcesto the viewer are dominated less by recycled light of the other

wavelengths, resulting in a significant reduction of color shift,especially in central portions of point spread functions of lightemitters in a display system that uses direct-lit light sources.

Notch filters and pass band filters, in conjunction with lightregeneration layers, may be used individually or in combination in adisplay system. These filters can also be deployed in differentindividual parts of a display system. In an example, either notchfilters, or pass band filters, or both types of filters, can beimplemented in conjunction with light regeneration layers in lightsources. In another example, either notch filters, or pass band filters,or both types of filters, can be implemented in conjunction with (e.g.,together with, etc.) light regeneration layers in one or more opticalstacks between light units and light modulation layers. In a furtherexample, either notch filters, or pass band filters, or both types offilters, can be implemented in conjunction with light regenerationlayers in one or more optical stacks between a viewer and one or morelight modulation layers; such optical stacks may, but are not limitedto, be implemented as a part of a pixel structure comprising colorfilters and/or liquid crystal cells.

In some embodiments, light sources with notch filters and/or pass bandfilters can be used to generate light of multiple (e.g., two, etc.)independent sets of primary colors. Light of a primary color in a firstset of primary colors and light of a corresponding primary color in asecond set of primary colors can have narrow wavelength ranges and/orhave little or no mutual overlap in light wavelengths. Accordingly,light of multiple sets of primary colors that have little or no mutualoverlap in light wavelengths can be emitted simultaneously in a displaysystem. The first set of primary colors can be used to render an imagefor a left eye perspective, while the second set of primary colors canbe used to render a corresponding image for a right eye perspective.Both images may together form a 3-dimensional (3D) image at the sametime or in a frame sequential manner. Thus, a viewer who wears 3Dglasses with a left eye glass transparent to the first set of primarycolors but opaque to the second set of primary colors and a right eyeglass transparent to the second set of primary colors but opaque to thefirst set of primary colors can perceive the 3D image renderedsimultaneously or in a frame sequential manner without needing tosynchronize with image rendering operations of the display system.

In some embodiments, a method comprises providing a display system asdescribed herein. In some possible embodiments, mechanisms as describedherein form a part of a display system, including but not limited to ahandheld device, tablet computer, theater system, outdoor display, gamemachine, television, laptop computer, netbook computer, cellularradiotelephone, electronic book reader, point of sale terminal, desktopcomputer, computer workstation, computer kiosk, PDA and various otherkinds of terminals and display units.

Various modifications to the preferred embodiments and the genericprinciples and features described herein will be readily apparent tothose skilled in the art. Thus, the disclosure is not intended to belimited to the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features described herein.

2. Structure Overview

One or more light regeneration layers (films, sheets, etc.) can be usedin an optical configuration of a display system. A light regenerationlayer may, but is not limited to, be formed by adding QD, RP, or otherlight regeneration materials to an (e.g., existing or new) opticallayer. Light regeneration materials may be coated, attached to, doped,or otherwise disposed on the top surface, the bottom surface, or bothsurfaces of the optical layer. Light regeneration materials may also beembedded within the optical layer. Light regeneration materials may bedisposed with the optical layer in any combination or order of variousdisposition methods.

FIG. 1A illustrates an example display system configuration comprising abacklight unit 110 (BLU), optical stack 1 (108), a light regenerationlayer 106, optical stack 2 (104), and a color filter layer (102). Pixelstructures can be implemented in one or more of the illustrated layersin FIG. 1A. In an example embodiment, pixel structures that are used tomodulate light intensity of transmissive light are embedded in the colorfilter layer (which may comprise filters of different colors forcorresponding subpixels) and optical stack 2 (which may comprise liquidcrystal unit structures for corresponding subpixels).

FIG. 1B illustrates an example side-lit display system configuration.FIG. 1C illustrates an example direct-lit display system configuration.In some embodiments, light sources as described in U.S. ProvisionalApplication No. 61/681,870, filed on Aug. 10, 2012, entitled “LIGHTDIRECTED MODULATION DISPLAYS,” the contents of which are herebyincorporated herein by reference for all purposes as if fully set forthherein, can be used with a display system as described herein. Asillustrated in FIG. 1B, one or more light sources 112-1 are configuredto inject light into a light guide in a BLU 110-1 in a side directionthat is different from (e.g., perpendicular to) a light transmissiondirection in which pixels are illuminated by transmissive light in theside-lit display system. In contrast, as illustrated in FIG. 1C, one ormore light sources 112-2 are configured to inject light into a lightguide in a BLU 110-2 in a direction that is similar to (e.g.,substantially aligned with) a light transmission direction in whichpixels are illuminated by transmissive light in the direct-lit displaysystem. Other light injection methods, including but limited to thosethat combine both side-lit and direct-lit light injection methods, mayalso be used in a display system as described herein.

Light injected by a light source (e.g., 112-1, 112-2, etc.) as describedherein may comprise one or more of a wide variety of light wavelengthdistribution patterns (spectral components of less than 1 nm, less than5 nm, between 5 nm and 30 nm inclusive, greater than 30 nm, etc.).Injected light in a BLU 110 may include but is not limited to: one ormore of blue light, violet light, ultraviolet light (including near(about 400-300 nm); middle (about 299-200 nm); far (about 199-122 nm),etc.

In some embodiments, light sources 112-1 and 112-2 of FIG. 1B and FIG.1C are configured to emit blue light; light regeneration layer 106comprises light regeneration materials configured to convert blue lightinto green and red light.

Color filters in display systems (e.g., LCD display systems) can varyfrom vendor to vendor. In some embodiments, color filters can bepreconfigured to absorb much of the light that does not have wavelengthsin pass bands of the color filters. In some embodiments, color filterscan be preconfigured to reject much of the light that does not havewavelengths in pass bands of the color filters. FIG. 2A illustratesexample transmittances 212, 214, and 216 versus wavelengths for blue,green, and red color filters, respectively. Since color filters aretypically optimized for light transmission and not color gamut,transmittances 212, 214, and 216 may have relatively large flatresponses over relatively large wavelength ranges that overlap with oneanother. As a result, a color filter of a specific color (e.g., blue,green, red, etc.) tends to pass a mixture of colors other than thespecific color, resulting in a desaturation of the specific color.

Light regeneration materials such as quantum dots can be selected togenerate light in specific bandwidth widths. To some extent, lightgeneration materials are typically cheaper when the bandwidth widths arewider. FIG. 2B illustrates example light spectral power distributions202, 204, and 206 respectively for blue light from a light pump/emitter(e.g., LED, light sources 112-1, light sources 112-2, etc.), green lightconverted from the blue light by a light regeneration layer (e.g., 106),and red light converted from the blue light by light regeneration layer106. It should be noted that other primary colors other than red, green,and blue colors may also be used. It should also be noted that more thanthree, three, fewer than three primary colors may be used in a colorsystem adopted by a display system.

Light may be reflected or bounced around at interfaces of differenttypes of light media in a display system as transmissive light travelsfrom a BLU to a viewer (not shown) located at the top of FIG. 1A, FIG.1B, and FIG. 1C. Additionally, optionally, or alternatively, lightreflectors, light scatter elements, optical retardation films, opticalwave plates, reflection enhancement films, prisms, etc., may beconfigured in a display system to recycle light. Some rejected lightwill be lost due to optical inefficiency, while some other rejectedlight can be recycled inside the light guide in the BLU (110-1) of theside-lit display system of FIG. 1B, in or at optical stack 1 (108), inor at light regeneration layer 106, in or at optical stack 2 (104), etc.The recycled light may be of a different light spectral powerdistribution (e.g., containing differentially attenuated/rejectedintermediate colors between primary colors, etc.) than that of 202 ofFIG. 2B, the latter of which represents the light spectral powerdistribution of blue light from a light pump/emitter (e.g., LED, lightsources 112-1, light sources 112-2, etc.).

When recycled light is incident on the light regeneration layer 106, aportion of the recycled light will be converted by the lightregeneration layer 106 to light of different (e.g., longer than that ofincident light, etc.) wavelengths than those of the recycled light. Aportion of converted/regenerated light may transmit through pixels to aviewer, while other portions of regenerated light may be furtherrejected and further recycled.

FIG. 2C illustrates example light spectral power distributions 222, 224,and 226, as viewed by a viewer through respective blue, green, and redcolor filters, taking into consideration recycled light. Primary colorlight as perceived by a viewer at the front of a display screen is notthe saturated color light as represented by light spectral powerdistributions 202, 204, and 206, but rather is significantly desaturatedcolor light as represented by light spectral power distributions 222,224, and 226 that contain bumps (e.g., local peaks or lobes) ofintermediate colors between the peaks of primary colors.

In some embodiments, light spectral power distributions 202, 204, and206, as illustrated in FIG. 2B, which respectively correspond to bluelight as emitted by light sources (e.g., 112-1, 112-2, etc.), greenlight as converted by light regeneration layer 106 from the blue light,and red light as converted by light regeneration layer 106 from the bluelight may have little or no mutual overlaps in light wavelengths. Incontrast, light spectral power distributions 222, 224, and 226, asillustrated in FIG. 2C, which respectively correspond to blue, green,and red light as transmitted through the color filters (e.g., in colorfilter layer 102) comprise significant mutual overlaps in lightwavelengths. The mutual overlaps exist because actual light incidentinto or at light regeneration layer 106 comprises both blue light fromlight emitters and light rays that are being recycled. The (effective)light spectral power distribution stimulating light regeneration layer106 may not be the same as that of light spectral power distribution 202of the light sources (e.g., 112-1, 112-2, etc.). Blue light exciteslight regeneration materials such as quantum dots more easily thannon-blue light and hence is converted to other colors of light moreeasily than non-blue light. In contrast, light of a non-blue color suchas green and red light does not excite the light regeneration materialsas much as the blue light, and hence is dispersed more widely than bluelight, as light is being recycled in various parts of the displaysystem. This can cause color shifts in, and yellow tails away from,central portions of point spread functions of light emitters. In analternative embodiment, light spectral power distribution 202 can bethat of a UV source, a broad light source, etc., converted into blue bylight regeneration layer 106. Accordingly, in this alternativeembodiment, the recycled light would then be the UV or broad lightsource, not blue.

3. Notch Filters

One or more notch filter layers (e.g., films, sheets, etc.) may be usedin an optical configuration of a display system. FIG. 3A illustrates anexample display system configuration comprising a BLU (110), opticalstack 1 (108), a notch filter layer (302), a light regeneration layer(106), optical stack 2 (104), and a color filter layer (102). FIG. 3Billustrates an example side-lit display system configuration thatcomprises one or more notch filter layers (e.g., 302). FIG. 3Cillustrates an example direct-lit display system configuration thatcomprises one or more notch filter layers (e.g., 302). FIG. 4Aillustrates an example transmittance 402 of notch filter layer 302.Transmittance 402 of notch filter layer 302 is preconfigured with one ormore notches (e.g., 404-1, 404-2, etc.). In an example, a notch (404-1)can be preconfigured in a bandwidth region between blue and green lightspectral power distributions 202 and 204, or between blue and greentransmittances 212 and 214. In another example, a notch (404-2) can bepreconfigured in a bandwidth region between green and red light spectralpower distributions 204 and 206, or between green and red transmittances214 and 216. In some embodiments, a notch filter layer can be configuredwith additional optical properties other than notches in thetransmittance response in specific wavelength ranges.

Other notches may also be configured in various possibleimplementations. For example, in embodiments in which UV light sourcesare used to create primary colors (e.g., red, green and blue) in a colorsystem (e.g. an RGB system, an RGB+ system, etc.), blue lightregeneration materials may be configured with a light regeneration layer(e.g., 106); one or more notches may be configured with a notch filterlayer (e.g., 302) between UV wavelengths and blue light wavelengths.

In some embodiments, a notch filter layer (e.g., 302) is disposed abovea light regeneration layer (e.g., 106), and is closer to the viewer thanthe light regeneration layer (106). The presence of notch filter layer302 rejects or reduces transmission of light in wavelengths thatcorrespond to the notches (e.g., 404-1, 404-2, etc.). Rejected light bynotch filter layer 302 may be recycled and sooner or later eitherabsorbed or converted into light in wavelengths that can be transmittedthrough notch filter layer 302.

FIG. 4B illustrates example light spectral power distributions 422, 424,and 426 (denoted as solid curves), as viewed by a viewer throughrespective blue, green, and red color filters. Color light as perceivedby a viewer is now a highly saturated color light, similar to thoserepresented by light spectral power distributions 202, 204, and 206,instead of desaturated color light as represented by light spectralpower distributions 222, 224, and 226 of FIG. 2C (denoted as dottedcurves in FIG. 4B). For example, as illustrated in FIG. 4B, intermediatecolors such as blue green and green red light, which exist in lightspectral power distributions 222, 224, and 226 of FIG. 2C are rejectedby notch filter layer 302. To avoid or reduce light loss, notch filterlayer 302 may comprise a rejection sheet or another light rejectionmechanism (e.g., dichroic mirrors, etc.) to direct rejected light awayfrom the viewer for further light recycling. Since there is at least onelight regeneration layer (e.g., 106, etc.) in the display system, whenrejected light hits light regeneration layer 106, the rejected light isreconverted to light of longer wavelengths. Some light fits in the passbands of notch filter layer 302 and color filter layer 102, goes throughnotch filter layer 302 and color filter layer 102, and producessaturated (or pure) colors to support wide color gamut displayoperations. Other light that (fits in the notches and) does not fit inthe pass bands of notch filter layer 302 and color filter layer 102,repeats the light regeneration/reconversion process.

In some embodiments, a notch filter layer can be configured orpreconfigured to filter as many light wavelengths in mutual overlapsbetween transmittances of different color filters as possible. In someembodiments, a notch filter layer can be designed based at least in parton further considerations relating to manufacturing processes, costs,color gamut requirements, etc.

Other methods of improving color saturation and supporting wide colorgamut may be used in conjunction with the use of one or more notchfilter layers. For example, light regeneration materials may be selectedwith wide separations between different primary colors (red, green, andblue, etc., in a RGB color system) in both injected and regeneratedlight. Light spectral power distributions of light sources may also bespecifically tuned to reduce bumps that are to be filtered out by notchfilter layers. In an example, stimulating light such as UV light, bluelight, etc., emitted by light sources may be configured with (e.g.,moved to, etc.) relatively short wavelengths away from green and redlight spectral power distributions as regenerated by light regenerationlayer 106 from the blue light. In another example, red light regeneratedby light regeneration layer 106 may be configured with (e.g., moved to,etc.) relatively long wavelengths away from those regenerated by lightregeneration layer 106.

4. Pass Band Filters

One or more band pass filter layers (films, sheets, etc.) may be used inan optical configuration of a display system. These band pass filterscan be configured to pass light in one or more specific wavelengthranges (pass bands). In an example, the specific wavelength ranges maybe in UV wavelength ranges for UV light sources if the UV light sourcesare used to excite light regeneration materials in the display system.In another example, the specific wavelength ranges may be in bluewavelength ranges for blue light sources if the blue light sources areused to excite light regeneration materials in the display system. Ifother light sources are used, the specific wavelength ranges may beselected to match wavelength ranges supported by the other lightsources.

FIG. 5A illustrates an example display system configuration comprising aBLU (110), optical stack 1 (108), a light regeneration layer (106), aband pass filter layer (502), optical stack 2 (104), and a color filterlayer (102). FIG. 5B illustrates an example side-lit display systemconfiguration that comprises one or more band pass filter layers (e.g.,502). FIG. 5C illustrates an example direct-lit display systemconfiguration that comprises one or more band pass filter layers (e.g.,302). FIG. 6 illustrates an example transmittance 602 of band passfilter layer 502. Transmittance 602 of band pass filter layer 502 ispreconfigured with one or more pass bands. In the illustratedembodiments in which blue light sources are used, a blue pass band isconfigured for transmittance 602 of band pass filter layer 502. Otherpass bands may also be configured in various possible implementations.For example, in embodiments in which UV light sources are used to createprimary colors (e.g., red, green and blue) in a color system (e.g. anRGB system, an RGB+ system, etc.), blue light regeneration materials maybe configured with a light regeneration layer (e.g., 106); one or morepass bands may be configured with a band pass filter layer (e.g., 502)in UV wavelength ranges.

In some embodiments, a band pass filter layer (e.g., 502) is disposedbelow a light regeneration layer (e.g., 106), and is further away fromthe viewer than the light regeneration layer (106). Light from the BLU110 initially passes through band pass filter layer 502. A portion ofthe initial light (e.g., blue, etc.) is converted by light regenerationlayer 106 to green and red light, while the other portion of the initiallight, which is not converted, passes through light regeneration layer106 as blue light. Blue light and converted light may be transmitted toa viewer; or rejected, reflected and/or redirected back towards BLU 110.For example, red and green filters may reject one or more portions ofinitial and converted light away from the direction of a viewer and backtoward BLU 110. Additional optical medium changes, if any, in opticalpaths towards the viewer may cause one or more portions of initial andconverted light to be redirected toward BLU 110.

Due to the optical properties (e.g., transmittance 602) of pass bandfilter 502, only light in the pass bands pass through, while light notin the pass bands is rejected back. Thus, the presence of pass bandfilter 502 keeps white light above pass band filter 502, and light inspecific pass bands below pass band filter 502. For example, inembodiments in which blue light sources are used, the presence of passband filter 502 keeps white light above pass band filter 502, and bluelight below pass band filter 502. Accordingly, light conversion islocalized to a specific spatial region in which light not in the passbands is trapped.

In embodiments in which UV light sources are used, only UV light passesinto a light recycling region between pass band filter 502 and BLU 110.Color light regenerated from UV light is rejected by pass band filter502 and redirect back towards the viewer. In embodiments in which bluelight sources are used, only blue light passes into a light recyclingregion between pass band filter 502 and BLU 110. Other (e.g., green andred) color light is rejected by pass band filter 502 and redirected backtoward the viewer. The presence of a band pass filter (502) recycles,and hence increases the amount of, converted light (as regenerated by alight regeneration layer (106)) toward the viewer. The converted lighttravels a much shorter optical path in reaching the viewer with thepresence of the band pass filter than otherwise. Without the presence ofa pass band filter, some portions of the converted light (e.g., non-UVlight, non-blue light, etc.) would travel relatively long optical paths,be redirected back to spatial regions close to or in light sources,spatially spread into wide angles and areas, and cause color shifts(e.g., yellow tails) as the rejected converted light dispersed furtheraway from light incident directions of the initial light from BLU 110.Without the presence of a pass band filter under techniques as describedherein, color shift degradation may be especially noticeable or evenvisually prominent in a direct-lit system. In such a system, forexample, the first pass light in the center of a point spread functionof a direct-lit light emitter would be mostly converted but rejectedlight component would likely bounce back in and convert with less greenand red as the distance from the center of the point spread function ofthe light emitter to out circumferences increases, giving rise to acolor shift to the point spread function.

5. Light Sources

Techniques as described herein can be used to generate two or more setsof primary colors in a color system. In some embodiments, the two ormore sets of primary colors at least comprise a first set of primarycolors, for example, a first primary red color (R1), a first primarygreen (G1), a first primary blue (B1), etc., in a RGB or RGB+ colorsystem; and a second set of primary colors, for example, a secondprimary red color (R2), a second primary green (G2), a second primaryblue (B2), etc., in the RGB or RGB+ color system.

FIG. 7A illustrates an example (front or back) light unit (110-3)comprising one or more first light sources (112-3) and one or moresecond light sources (112-4), one or more first light regenerationlayers (106-1), one or more second light regeneration layers (106-2),one or more first filter layers (302-1), one or more second filterlayers (302-2), and a light recycling region 702 (which may be a lightguide in some implementations). Light sources (e.g., 112-3, 112-4, etc.)as described herein may be configured in any of the same side/wall, ormore than one—e.g., two, three, four, etc.—side(s)/wall(s). For example,FIG. 7B illustrates an alternative configuration in which light sources112-2 and 112-4 in light unit 110-3 are located along the sameside/wall.

Light unit 110-3 can be configured to emit and/or regenerate more thanone set of primary colors. Light recycling region 702 can be configuredwith one or more light directing components to direct the generated andregenerated light in light recycling region towards a viewer of adisplay system that operates with light unit (110-3).

In some embodiments, light unit 110-3 is configured to generate thefirst and second sets of primary colors as mentioned above. The one ormore first light sources (112-3), the one or more first lightregeneration layers (106-1) and the one or more first filter layers(302-1) are configured to generate or regenerate the first set ofprimary colors, whereas the one or more second light sources (112-4),the one or more second light regeneration layers (106-2) and the one ormore second filter layers (302-2) are configured to generate orregenerate the second set of primary colors.

In some embodiments, the one or more first light sources (112-3) areconfigured to emit blue light of a wavelength composition that coverswavelengths of the first blue light (B1); the one or more first lightregeneration layers (106-1) are configured to regenerate red light of awavelength composition that covers wavelengths of the first red light(R1) and green light of a wavelength composition that covers wavelengthsof the first green light (G1). In some embodiments, the one or moresecond light sources (112-4) are configured to emit blue light of awavelength composition that covers wavelengths of the second blue light(B2); the one or more second light regeneration layers (106-2) areconfigured to regenerate red light of a wavelength composition thatcovers wavelengths of the second red light (R2) and green light of awavelength composition that covers wavelengths of the second green light(G2). In various embodiments, other permutations (color composition) ofinitial light from light emitters and converted light (colorcomposition) from light regeneration materials may be used to generatethe first and second sets of primary colors.

FIG. 8 illustrates example light spectral power distributions 202-1 and202-2 generated by first light sources (112-3) and second light sources(112-4), respectively; example light spectral power distributions 204-1and 204-2 generated by first light regeneration layers (106-1) andsecond light regeneration layers (106-2), respectively; example lightspectral power distributions 206-1 and 206-2 generated by first lightregeneration layers (106-1) and second light regeneration layers(106-2), respectively; and example transmittances 402-1 and 402-2 offirst filter layers 302-1 and second filter layers 302-2, respectively.It should be noted that techniques as described herein for 3D or non-3Ddisplay operations may be used with a wide variety of color filtersincluding those (which, for example, may be of transmittances 212, 214and 216 of FIG. 2A) that have mutual overlaps in bandwidths.

In some embodiments, transmittance 402-1 of first filter layers 302-1 isconfigured or preconfigured with one or more first opaque or lowtransmittance ranges (e.g., first notches, etc.). In an example, thefirst low transmittance ranges can be configured or preconfiguredbetween first blue and green light spectral power distributions 202-1and 204-1 and between first green and red light spectral powerdistributions 204-1 and 206-1. Likewise, transmittance 402-2 of secondfilter layers 302-2 can be configured or preconfigured with one or moresecond opaque or low transmittance ranges (e.g., second notches, etc.).In an example, the second low transmittance ranges can be configured orpreconfigured between second blue and green light spectral powerdistributions 202-2 and 204-2 and between second green and red lightspectral power distributions 204-2 and 206-2.

Other types of filters may also be configured or pre-configured invarious possible implementations. For example, in embodiments in whichUV light sources are used to create sets of primary colors (e.g., red,green and blue) in a color system (e.g. an RGB system, an RGB+ system,etc.), two different types of blue light regeneration materials may beconfigured with light regeneration layers (e.g., 106-1 and 106-2) inaddition to different types of green light regeneration materials anddifferent types of red light regeneration materials; opaque or lowtransmittance regions may be configured with filter layers (e.g., 302-1and 302-2) between UV wavelengths and different types of blue lightwavelengths in addition to opaque or low transmittance regions betweenrespective different colors in the two sets of primary colors.

Additionally, optionally, or alternatively, pass band filter layers maybe provisioned between light sources (112-3, 112-4, etc.) and lightregeneration layers (302-1, 302-2, etc.). These pass band filter layerscan increase efficiency by trapping/retaining converted light from thelight regeneration layers (302-1, 302-2, etc.) within light recyclingregion 702 so that the converted light can be redirected in lightrecycling region 702 to a viewer.

Using filter layers as illustrated in FIG. 7A and FIG. 7B, primarycolors as viewed by a viewer through respective blue, green, and redcolor filters are now highly saturated color light. Overlappedwavelengths and/or notches as illustrated in FIG. 2C that causedesaturated primary colors are avoided or significantly reduced,resulting in much improvement in wide color gamut display operations.

Two different sets of primary colors, each of which comprises a full setof primary color in a color system, can be used to support 3-dimensional(3D) display operations. A first set of primary colors (e.g., R1, G1,B1, etc.) can be used to render a left view image, while a second set ofprimary colors (e.g., R2, G2, B2, etc.) can be used to render a rightview image. The left view and right view images together form a 3Dimage.

In some embodiments, light wavelengths of the first set of primarycolors (R1, G1 and B1) have no or little overlapping with lightwavelengths of the second set of primary colors (R2, G2 and B2). Aviewer may wear a pair of glasses with a left perspective configured tobe transmissive for one set in the first and second sets of primarycolors but opaque for the other set in the first and second sets ofprimary colors, and with a right perspective configured to be opaque forthe one set in the first and second sets of primary colors buttransmissive for the other set in the first and second sets of primarycolors. Under techniques as described herein, synchronization between aviewer's glasses and image rendering operations of a 3D display systemis not needed in 3D display applications.

6. Pixel Structures

One or more light regeneration layers can be integrated in a displaysystem outside pixel structures (e.g., disposed outside or inside alight unit), as well as inside pixel structures. FIG. 9A illustrates anexample pixel structure comprising a plurality of pixels (one of whichis pixel 906-1). For the purpose of illustration only, pixel 906-1comprises three subpixels each of which comprises a color filter (e.g.,902) and a liquid crystal cell (904). Color filter 902 is a part of acolor filter array, whereas liquid crystal cell 904 is a part of liquidcrystal cell array. Liquid crystal cell 904 is configured to modulatewhite transmissive light directed at a viewer along the up direction ofFIG. 9A. The modulated white transmissive light subsequently hits colorfilter 902, which may be configured to impart a primary color such asred color in a RGB or RGB+ color system. A portion of modulated whitetransmissive light becomes filtered light (e.g., red light) directed atthe viewer, while the remaining portion (e.g., blue light, green light,a portion of red light, etc.) of modulated white transmissive light isabsorbed and/or rejected by color filter 902. Thus, a significant amount(>>50%) of light is lost, resulting in an optically inefficient displaysystem.

FIG. 9B illustrates an example pixel structure comprising a plurality ofpixels (one of which is pixel 906-2) configured with a lightregeneration layer 908-1 between color filters and liquid crystal cells.Light regeneration layer 908-1 is configured with light regenerationmaterials to convert incident light of certain wavelengths intoregenerated light of certain other wavelengths. For example, lightregeneration layer 908-1 comprises a homogeneous composition/structureconfigured to convert UV into blue, green and red light, convert bluelight into green light, convert blue light into red light, and/orconvert green light into red light. Additionally, optionally, oralternatively, light regeneration layer 908-1 comprises a black matrixsimilar to, or as an extension of, that of the color filter array. Theblack matrix can be configured to prevent light leakage betweendifferent subpixels and/or between different pixels.

In a first implementation example, similar to that of FIG. 9A, liquidcrystal cell 904 of FIG. 9B is configured to receive and modulate whitetransmissive light directed at a viewer along the up direction. Themodulated white transmissive light subsequently hits light regenerationlayer 908-1. Light regeneration layer 908-1 is configured to regenerategreen and red light from a portion of the modulated white light (e.g.,blue and/or green light) and to pass the remaining portion of themodulated white light. The passed portion of the modulated white lightand regenerated green and red light hit color filter 902, which may beconfigured to impart a primary color such as red color in a RGB or RGB+color system. A portion of incident light at color filter 902 becomesfiltered light (e.g., red light) directed at the viewer, the remainingportion (e.g., blue light, green light, a portion of red light, etc.) ofthe incident light, other than the filtered light or light loss due toabsorption, as rejected by color filter 902, is at least partiallyrecycled and converted to usable light (e.g., red light for the subpixelcomprising color filter 902 and liquid crystal cell 904) by lightregeneration layer 908-1, resulting in an optically efficient displaysystem relative to a display system of FIG. 9A.

In a second implementation example, liquid crystal cell 904 isconfigured to receive and modulate blue transmissive light directed at aviewer along the up direction of FIG. 9A. The modulated bluetransmissive light subsequently hits light regeneration layer 908-1.Light regeneration layer 908-1 is configured to regenerate green and redlight from a portion of blue light and to pass the remaining portion ofblue light. Blue light and regenerated green and red light hit colorfilter 902, which may be configured to impart a primary color such asred color in a RGB or RGB+ color system. A portion of incident light atcolor filter 902 becomes filtered light (e.g., red light) directed atthe viewer, while the remaining portion of the incident light isabsorbed and/or rejected by color filter 902. The incident light notlost to absorption, as rejected by color filter 902, is at leastpartially recycled and converted to usable light (e.g., red light forthe subpixel comprising color filter 902 and liquid crystal cell 904) bylight regeneration layer 908-1, resulting in an optically efficientdisplay system relative to a display system of FIG. 9A.

In a third implementation example, liquid crystal cell 904 of FIG. 9B isconfigured to receive and modulate UV light directed at a viewer alongthe up direction. The modulated UV transmissive light subsequently hitslight regeneration layer 908-1. Light regeneration layer 908-1 isconfigured to regenerate blue, green and red light from the modulated UVlight and other incident light (e.g., UV, blue and/or green light). Theregenerated blue, green and red light hits and at least partially passesthrough color filter 902, which may be configured to impart/pass aprimary color such as red color in a RGB or RGB+ color system. A portionof incident light at color filter 902 becomes filtered light (e.g., redlight) directed at the viewer, the remaining portion (e.g., blue light,green light, a portion of red light, etc.) of the incident light, otherthan the filtered light or light loss due to absorption, as rejected bycolor filter 902, is at least partially recycled and converted to usablelight (e.g., red light for the subpixel comprising color filter 902 andliquid crystal cell 904) by light regeneration layer 908-1, resulting inan optically efficient display system relative to a display system ofFIG. 9A.

FIG. 9C illustrates an example pixel structure comprising a plurality ofpixels (one of which is pixel 906-2) configured with a lightregeneration layer 908-2 between color filters and liquid crystal cells.Light regeneration layer 908-2 is configured with light regenerationmaterials to convert incident light of certain wavelengths intoregenerated light of certain other wavelengths. For example, lightregeneration layer 908-2 comprises a patterned composition/structure,which corresponds to the subpixel or pixel structure of the colorfilters and the liquid crystal cells. A light regeneration unit 910 (inlight regeneration layer 908-2) that corresponds to color filter 902 andliquid crystal cell 904 in a red subpixel or pixel can be configured toconvert other light such as UV, blue and/or green light into red light.A light regeneration unit (in light regeneration layer 908-2) in a greensubpixel or pixel can be configured to convert other light such as UVand/or blue light into green light. A light regeneration unit (in lightregeneration layer 908-2) in a blue subpixel or pixel can be configuredto convert other light such as UV light into blue light and/or pass bluelight. Additionally, optionally, or alternatively, light regenerationlayer 908-1 comprises a black matrix similar to, or as an extension of,that of the color filter array. The black matrix can be configured(e.g., with opaque metallic or non-metallic materials, lightregeneration materials that generate invisible infrared light, etc.) toprevent light leakage between different subpixels and/or betweendifferent pixels.

Liquid crystal cells in FIG. 9C may be illuminated by one or more ofdifferent types of transmissive light (e.g., UV light, blue light,etc.). Due to the presence of light regeneration layer 908-2, theremaining portion of the incident light, other than the filtered lightor light loss due to absorption, as rejected by the color filter, is atleast partially recycled and converted to usable light by lightregeneration layer 908-2, resulting in an optically efficient displaysystem relative to a display system of FIG. 9A. FIG. 9D illustrates analternative example pixel structure to the pixel structure depicted inFIG. 9C. The light regeneration layer 908-2 may be placed below theliquid crystal cells and the color filters. Thus, the liquid crystalcells and the color filters form a LCD panel. The light regenerationlayer 908-2 comprises a pixel structure in which light regenerationunits of different colors are aligned respectively with color filters ofthe different colors. Also, there can be (optionally) intervening layers(e.g., BEF/DBEF, etc.) above or under the light regeneration layer. Itshould be noted that the rectangular shapes used in FIG. 9C and FIG. 9Dto represent light regeneration units are for illustration purposesonly. Other shapes may be used to implement the light regenerationunits. In some embodiments, for example, shapes of light regenerationunits in a light regeneration layer as described herein can beconfigured to be lenticular in order to focus/collimate light towardscolor filters.

Additionally, optionally, or alternatively, a black matrix as describedherein, may be configured with light regeneration materials that convertblue, green and/or red light into longer wavelengths (e.g., wavelengthsof invisible light such as infrared, etc.) and hence prevent lightleakages between different subpixels and/or between different pixels. Insome embodiments, a black matrix is disposed between color filters in acolor filter array. The black matrix may be configured with lightregeneration materials that convert visible light to invisible lightsuch as infrared light in addition to, or in place of, light absorptionmaterials. Light leaked through a liquid crystal cell (e.g., in a closedstate, in a dark state, etc.) may be diverted to the black matrix. Oneor more light diverting mechanisms can be configured in a pixelstructure to divert light from dark state liquid crystal cells to theblack matrix in order to produce deeper black levels in subpixels orpixels that represent dark pixel values in image data to be rendered ina display system.

Additionally, optionally, or alternatively, light regeneration materialsused in a light regeneration layer as described herein may be configuredto create wideband colors, medium band colors, narrow band colors,combinations of the foregoing, etc. For example, liquid regenerationmaterials can be selected to emit narrow band color light configured tosupport wide color gamut or 3D display applications.

Additionally, optionally, or alternatively, notch filters and pass bandfilters may be configured with a light regeneration layer implemented insubpixel or pixel structures such as illustrated in FIG. 9B and FIG. 9C.These notch filters and pass band filters may be used to improve opticalefficiency and/or color gamut, to produce saturated colors, to support3D display applications, etc.

FIG. 10A illustrates an example pixel with color filters (1002-1, 1002-2and 1002-3) covering red, green and blue subpixels in the pixel. Atransparent conductive layer such as an ITO film may be formed overcolor filters 1002-1, 1002-2 and 1002-3. Color filters and a blackmatrix that separates color filters of different subpixels may bepatterned in stripes using photolithography. Color filters 1002-1,1002-2 and 1002-3 may be formed or disposed on or near a front substrate(e.g., glass, etc.). The front substrate (along with another substratebetween Liquid crystal cells and a BLU may be used to encapsulate Liquidcrystal materials in the Liquid crystal cells. The Liquid crystal cellsmay be illuminated with white light. Color filters 1002-1, 1002-2 and1002-3 may comprise passive color pigments supporting high contrastdisplay operations.

FIG. 10B illustrates an example pixel with color and colorless filters(1002-4, 1002-5 and 1002-6) covering red, green and blue subpixels inthe pixel. Color filters 1002-4 and 1002-5 comprise red and green lightregeneration materials, respectively; and cover red and green subpixelsin the pixel, respectively. Colorless filter 1002-6 (e.g., a transparentbinder material) may be used to cover a blue subpixel in the pixel. TheLiquid crystal cells may be illuminated with blue light instead of whitelight.

FIG. 10C illustrates an example pixel. An ITO layer may be patterned ona mid-glass with a polarizer layer on top of the mid-glass. A top(contiguous) filter layer comprising a blue dichroic mirror or yellowpigments is disposed or formed near or above a red light regenerationlayer (red LRL) and a green light regeneration layer (green LRL). Thered and green LRLs can emit light in all directions; however, the topfilter layer can be configured (e.g., with light-redirectingmicrostructures, etc.) to redirect red and green light in the forwarddirection (along the up direction of FIG. 10C). A bottom (contiguous)filter layer comprising a yellow dichroic mirror is disposed or formednear or under the red LRL, the green LRL and a transparent layer in ablue pixel of the pixel. The bottom filter layer is configured to passblue light and hence has no filtering effect in the blue subpixel. Insome embodiments, black matrix elements may, but do not need to, bepresent around the transparent layer in the blue subpixel. The topfilter layer absorbs ambient light incident from the top, and preventsor lessens stimulations of the light generation materials in the red andgreen LRLs; otherwise, the stimulations of the light generationmaterials in the red and green LRLs by ambient light would cause a risein lowest achievable dark level which would in turn reduce contrast indisplay operations. The placements of polarizer layers andanti-reflection (AR) layers are depicted for illustration purposes only.Other placement choices or spatial arrangements other than that depictedin FIG. 10C or other figures may be used. In some embodiments, one ormore transparent materials may be disposed above the bottom filter layerin the blue pixel of the pixel.

FIG. 10D illustrates an alternative configuration to that of the pixeldepicted in FIG. 10C. The pixel of FIG. 10D comprises two separate redand green dichroic mirrors in red and green subpixels, respectively,instead of a yellow dichroic mirror for both red and green subpixels asillustrated in FIG. 10C. Transmittances of red and green dichroicmirrors can be adjusted to narrow frequency bands of light regeneratedby the red and green LRLs, in order to improve color gamut in a displaysystem which implements the pixel configuration of FIG. 10D.

FIG. 10E illustrates an alternative configuration to that of the pixeldepicted in FIG. 10C. The pixel of FIG. 10E comprises a UV blockinglayer at least in red and green subpixels, instead of a yellow dichroicmirror in red and green subpixels as illustrated in FIG. 10C. The UVblocking layer prevents ambient light from stimulating the red and greenLRL. This reduces light emissions from the red and green LRL caused byambient light when modulated transmissive light is at the lowest level(lowest achievable dark level). Accordingly, both contrast and dynamicrange in display operations can be improved.

FIG. 10F illustrates an alternative configuration to that of the pixeldepicted in FIG. 10C. The top glass of FIG. 10C is replaced with a UVblocking layer. The top filter layer of FIG. 10C is removed. As in FIG.10E, the presence of the UV blocking layer reduces light emissions fromthe red and green LRL caused by ambient light when modulatedtransmissive light is at the lowest level (lowest achievable darklevel). Accordingly, both contrast and dynamic range in displayoperations can be improved. The pixel configuration of FIG. 10F islikely a low cost solution to make and to produce relatively highcontrast.

As described herein, a substrate or glass (e.g., the top glass, coverclass, etc.) can be relatively thin to avoid or reduce cross talk orlight leakage (for both stimulating and stimulated light). A substrateor glass may be implemented in a large TV size using a Gorilla type orother types of substrates or glasses. Additionally, optionally, oralternatively, yellow dichroic mirrors may be coated on a cover glassfollowed by color filters and a smoothing layer.

It should be noted that display system configurations, light unitconfigurations and pixel configurations in figures herein are providedfor illustration purposes only. Other configurations, permutations,combinations, types of components or layers, etc., may be used inimplementing techniques as described herein.

For projection and display purposes it can be desirable to have controlover the spectral power distribution (SPD) of a light source. In commonapproaches, the SPD of a light source is fixed, for example, due to thelight source's physical or chemical composition. Even when using an RGBLED system, only the relative intensities of component LEDs' SPDs can bechanged, but not the distribution of the whole power spectrum (e.g.,shifting the peak wavelength of one of the LEDs).

Under techniques as described herein, a light regeneration layer (e.g.,a spatial gradient quantum dots sheet/film, light regeneration materialsof specific spectral distributions and densities/concentrations, etc.)may be used to shape the SPD of a light source. The approach under thesetechniques does not have the limitations of other approaches, since theSPD of the light source can be shaped arbitrarily under the approach byusing spatial light modulating device and a light regeneration layer,which for example may be configured to convert spatially modulated lightinto spectrally modulated light, as will be further discussed in detail.

The same techniques can be used to de-speckle lasers by widening anarrow bandwidth SPD of a laser-based light source into light of abroader bandwidth SPD. Particularly, a narrow band light from a lasersource can be converted by quantum dots to a wider band collimatedlight.

7. Shaping Spectral Power Distributions

FIG. 11 illustrates shaping SPD with light from a narrow band lasersource. A short wavelength laser (e.g. blue) shown in Step 1 emits anarrow band (monochromatic) beam. This beam is (e.g., uniformly,non-uniformly, etc.) widened in Step 2 and projected onto a spatiallight modulating device shown in Step 3—which can be a digital mirrordevice or DMD, etc. Additionally, optionally, or alternatively, a laserscanning device, which can be a galvanometer, moving/oscillating MEMSdevice, etc.—may be used in place of, or in addition to, beam expandingoptics in Step 2 to spatially modulate the blue laser beam. The DMD orgalvanometer can be 1D or 2D, depending on the required complexity aswell as energy throughput of the system.

The spatially modulated light is projected on a gradient quantum dotsheet (Step 4). ‘Gradient’ in this context means that the regeneratedlight wavelength properties of the quantum dots vary spatially over thearea of the sheet. For example, for monochromatic blue laser lighthitting the left side of the sheet (A), the quantum dot properties couldbe set to convert to 400 nm while the same input light can be convertedto 780 nm on the right side of the sheet (B). Spatial areas in-between Aand B can cover the wavebands in-between 400 and 780 nm. It should benoted that the spatial quantum dot gradient does not have to be uniformor even monotonically increasing. Instead, any kind of gradientdistribution is possible such as a weighting of primary colors inregenerated light used in digital projection systems or having widerwavebands at any given spatial position. For example, areas close toside A can convert the input monochromatic laser light to CIE illuminantA, while areas close to side B can convert the input monochromatic laserlight to CIE illuminant D65, thereby optimizing the total energythroughput of the system. The light leaving the gradient quantum dotssheet is now spectrally modulated as a function of the spatial setup ofthe galvanometer or DMD described in Step 3.

The gradient quantum dot sheets may scatter the output light intodifferent spatial directions or direction ranges to some extent. Thescattered light can be collimated again to avoid or reduce energy lossand to improve efficiency. This can be achieved using a fiber opticscollimator illustrated in Step 5. In some embodiments, the spatialorientation and position may no longer be critical; any kind of lightcollimation (e.g., lenses, mirrors, different forms of total innerreflection, etc.) can be implemented. In some embodiments, the desiredoutput of the light system is a spatially uniform beam of light that hasa desired SPD defined by the spatial setting of the galvanometer or DMD.The mirror shown in Step 6 is a broadband mirror to reflect the lightback into the optical path direction of the original laser but can alsobe left out or replaced with other optical elements such as lenses oroptical filters.

Example SPDs are illustrated in FIG. 11. As shown, the narrow band widthblue laser beam is converted to an SPD of a CCFL light source.

An alternative form to using a complex spatial light modulation devicesuch as galvanometer or DMD is using a light path switch which can forexample be used to physically switch the laser beam to a particular(uniform, not gradient) area on a quantum dot sheet. With thisalternative approach, changing the white point of a display system, forexample from D65 to D50, can be implemented without sacrificing lightenergy as it would be commonly the case under other approaches that donot implement the techniques as described herein.

Techniques as described herein can be implemented in projection systemsor in back-lit systems. As the spatial composition of the gradientquantum dots sheet can be flexibly optimized to a specific displayapplication, the light source can be very efficient and thus costeffective.

Efficiency can be improved by using quantum dot color arrays or phosphorcolor arrays instead of color filter arrays that are used to impartcolors in color display systems. A red quantum dot or phosphor materialabsorbs light of higher energies or shorter wavelengths such as greenand blue light and emits red light. A green quantum dot or phosphormaterial absorbs blue light and emit green light. Higher systemefficiency can be achieved by replacing the (passive pigment-based) redfilter with red quantum dot or red phosphor materials, the green filterwith green quantum dot or green phosphor materials, and the blue filterwith a clear filter, operating in conjunction with a display systembacklit with blue LEDs or with a display system using blue OLED. Insteadof producing broadband light and then blocked by the color filters toproduce the desired colors, the red and green light can be emitted byconverting from blue light source and blue light is emitted directlywithout filtering from the blue light source.

Quantum dots and phosphors may be processed by photolithographictechniques. Color filter materials could be inert or passive pigments ordyes that are mixed into photoresist materials in the photolithographicprocess during color filter construction. In contrast, quantum dots andphosphor materials tend to be active, sensitive to environment andsurround chemicals. Various techniques including but not limited to anyof: printing techniques, photolithographic techniques, etc., can be usedto deposit the quantum dot or phosphor into color array patterns.

8. Color Array Panels

Techniques as described herein can be used to construct color arraypanels having strips of quantum dots or phosphors by processing thinsheets of materials having quantum dots or phosphors.

In some embodiment, sheets of materials having sheet thicknesses thatmatch the subpixel pitch of a target display where each pixel containsmultiple subpixels that can be stacked in sequence to construct a colorarray panel. A first sheet contains red quantum dot or phosphormaterials and is referred to as Sheet R. A second sheet contains greenquantum dot or phosphor materials and is referred to as Sheet G. Apassive filler sheet without quantum dots or phosphors is referred to asSheet W. FIG. 12 illustrates an example configuration in which thesheets are stacked in a sequence of Sheet R, Sheet G and Sheet W,wherein respective sheet thicknesses of Sheet R, Sheet G and Sheet Wmatch the respective subpixel pitches of red, green and blue subpixelsof pixels.

The color array panel may be used to replace the color filter array in acolor LCD or OLED display. System efficiency can be improvedsignificantly by reducing wasted light. In an example, an LCD panel canbe manufactured as a monochrome panel backlit by blue backlight andwithout color filters. In another example, an OLED display can beconstructed as a blue OLED panel only instead of white OLED with colorfilters. The color array panel comprising quantum dot or phosphormaterials can be added in front of (as illustrated in FIG. 13), behindthe monochrome LCD panel, or even behind an optical film (e.g., DualBrightness Enhancement Films (DBEF), reflective polarizers, etc.).Similarly, for an OLED display, the color array panel comprising quantumdot or phosphor materials can be added in front of (as illustrated inFIG. 13).

FIG. 14 illustrates example steps in constructing a color array panel asdescribed herein. In Step 1 of FIG. 14, raw sheets are reduced tothicknesses that match target subpixel pitches. This step may beaccomplished by passing the sheets through heated rollers. Operationalparameters such as roller temperature, roll rate, roller separation,etc., may be controlled by industrial control system to achieve thetarget thicknesses. Examples of raw sheets include but are not limitedto: plastics containing quantum dots or phosphors. Step 1 of FIG. 14 isapplied to all of different color sheets containing quantum dots orphosphors as well as filler sheets which do not contain any quantum dotsor phosphors.

In Step 2 of FIG. 14, the sheets processed by Step 1 of FIG. 14 arestacked in a desired sequence (e.g., matching the sequence of differentcolor subpixels) and bonded. A stack thickness equals the totalthickness contributed from each of different color sheets and a fillersheet. The stack thickness may be further reduced to ensure matching atarget pixel pitch which equals the total thickness contributed fromeach of different color subpixels (e.g., RGB subpixels in a RGB colorsystem, other color subpixels in a non-RGB color system, etc.). Opticalmeasurements for quality control may be made in Step 2 of FIG. 14 toensure the stack thickness and sheet thicknesses match the pixel pitchand subpixel pitches.

In Step 3 of FIG. 14, the stack is sliced into strips of uniform widths.The strip width determines the final thickness of the color array panel.The cutting can be accomplished by mechanical means involving physicalcontact with the material or by laser cutting.

In Step 4 of FIG. 14, the strips are rotated by 90° axially and then therotated strips are stacked to form the (final) color array panel. Theprocess may be applied on continuous rolls of the raw materials.

In display operations, the blue light from the backlight of an LCD orfrom a blue OLED is either converted to red light by the red strip orgreen light by the green strip, and/or diffused through the fillerstrip. The thickness of the color array panel can be used as a designparameter to control a preconfigured white point of the display panelcomprising the color array panel. The panel thickness affects theoptical path lengths and likelihood with which incident blue light maybe converted to the red and green light. Thus, the strip width in Step 3of the example construction process of the color array panel in FIG. 14can be used to control the display panel to realize the desired whitepoint.

Color array panels can be manufactured to adapt to different pixelpitches since for a given display size there are usually a range ofdisplay resolution available. It should also be noted that for a LCD andan OLED of the same pixel pitch, a color array panel can be selected andapplied to either display without extra customization.

9. Light Source Control Logic

FIG. 15 illustrates an example configuration of display logic (1502) ina display system as described herein, in accordance with some possibleembodiments of the present invention. In some possible embodiments,display logic 1502 additionally and/or optionally may comprise lightsource control logic (1504) configured to control component(s) in alight source (e.g., BLU 110) in the display system. The display logic1502 may be operatively coupled with an image data source 1506 (e.g., aset-top box, networked server, storage media or the like) and isconfigured to receive image data from the image data source 1506. Theimage data may be provided by the image data source 1506 in a variety ofways including from an over-the-air broadcast, or Ethernet,High-Definition Multimedia Interface (HDMI), wireless network interface,devices (e.g., set-top box, server, storage medium, etc.), etc. Imageframes received or generated from image data from an internal orexternal source may be used by the display logic 1502 to drive the lightsource in the display system. For example, display logic 1502 may beconfigured to control the light source to illuminate one or more pixelsor sub-pixels with a specific intensity. The image frames may be used bythe display logic 1502 to derive individual or aggregate pixel values invarious frames in various resolutions on an image rendering surface asdescribed herein.

10. Implementation Mechanisms—Hardware Overview

According to one embodiment, the techniques described herein areimplemented by one or more special-purpose computing devices. Thespecial-purpose computing devices may be hard-wired to perform thetechniques, or may include digital electronic devices such as one ormore application-specific integrated circuits (ASICs) or fieldprogrammable gate arrays (FPGAs) that are persistently programmed toperform the techniques, or may include one or more general purposehardware processors programmed to perform the techniques pursuant toprogram instructions in firmware, memory, other storage, or acombination. Such special-purpose computing devices may also combinecustom hard-wired logic, ASICs, or FPGAs with custom programming toaccomplish the techniques. The special-purpose computing devices may bedesktop computer systems, portable computer systems, handheld devices,networking devices or any other device that incorporates hard-wiredand/or program logic to implement the techniques.

For example, FIG. 16 is a block diagram that illustrates a computersystem 1600 upon which an embodiment of the invention may beimplemented. Computer system 1600 includes a bus 1602 or othercommunication mechanism for communicating information, and a hardwareprocessor 1604 coupled with bus 1602 for processing information.Hardware processor 1604 may be, for example, a general purposemicroprocessor.

Computer system 1600 also includes a main memory 1606, such as a randomaccess memory (RAM) or other dynamic storage device, coupled to bus 1602for storing information and instructions to be executed by processor1604. Main memory 1606 also may be used for storing temporary variablesor other intermediate information during execution of instructions to beexecuted by processor 1604. Such instructions, when stored innon-transitory storage media accessible to processor 1604, rendercomputer system 1600 into a special-purpose machine that is customizedto perform the operations specified in the instructions.

Computer system 1600 further includes a read only memory (ROM) 1608 orother static storage device coupled to bus 1602 for storing staticinformation and instructions for processor 1604. A storage device 1610,such as a magnetic disk or optical disk, is provided and coupled to bus1602 for storing information and instructions.

Computer system 1600 may be coupled via bus 1602 to a display 1612, suchas a liquid crystal display, for displaying information to a computeruser. An input device 1614, including alphanumeric and other keys, iscoupled to bus 1602 for communicating information and command selectionsto processor 1604. Another type of user input device is cursor control1616, such as a mouse, a trackball, or cursor direction keys forcommunicating direction information and command selections to processor1604 and for controlling cursor movement on display 1612. This inputdevice typically has two degrees of freedom in two axes, a first axis(e.g., x) and a second axis (e.g., y), that allows the device to specifypositions in a plane.

Computer system 1600 may implement the techniques described herein usingcustomized hard-wired logic, one or more ASICs or FPGAs, firmware and/orprogram logic which in combination with the computer system causes orprograms computer system 1600 to be a special-purpose machine. Accordingto one embodiment, the techniques as described herein are performed bycomputer system 1600 in response to processor 1604 executing one or moresequences of one or more instructions contained in main memory 1606.Such instructions may be read into main memory 1606 from another storagemedium, such as storage device 1610. Execution of the sequences ofinstructions contained in main memory 1606 causes processor 1604 toperform the process steps described herein. In alternative embodiments,hard-wired circuitry may be used in place of or in combination withsoftware instructions.

The term “storage media” as used herein refers to any non-transitorymedia that store data and/or instructions that cause a machine tooperation in a specific fashion. Such storage media may comprisenon-volatile media and/or volatile media. Non-volatile media includes,for example, optical or magnetic disks, such as storage device 1610.Volatile media includes dynamic memory, such as main memory 1606. Commonforms of storage media include, for example, a floppy disk, a flexibledisk, hard disk, solid state drive, magnetic tape, or any other magneticdata storage medium, a CD-ROM, any other optical data storage medium,any physical medium with patterns of holes, a RAM, a PROM, and EPROM, aFLASH-EPROM, NVRAM, any other memory chip or cartridge.

Storage media is distinct from but may be used in conjunction withtransmission media. Transmission media participates in transferringinformation between storage media. For example, transmission mediaincludes coaxial cables, copper wire and fiber optics, including thewires that comprise bus 1602. Transmission media can also take the formof acoustic or light waves, such as those generated during radio-waveand infra-red data communications.

Various forms of media may be involved in carrying one or more sequencesof one or more instructions to processor 1604 for execution. Forexample, the instructions may initially be carried on a magnetic disk orsolid state drive of a remote computer. The remote computer can load theinstructions into its dynamic memory and send the instructions over atelephone line using a modem. A modem local to computer system 1600 canreceive the data on the telephone line and use an infra-red transmitterto convert the data to an infra-red signal. An infra-red detector canreceive the data carried in the infra-red signal and appropriatecircuitry can place the data on bus 1602. Bus 1602 carries the data tomain memory 1606, from which processor 1604 retrieves and executes theinstructions. The instructions received by main memory 1606 mayoptionally be stored on storage device 1610 either before or afterexecution by processor 1604.

Computer system 1600 also includes a communication interface 1618coupled to bus 1602. Communication interface 1618 provides a two-waydata communication coupling to a network link 1620 that is connected toa local network 1622. For example, communication interface 1618 may bean integrated services digital network (ISDN) card, cable modem,satellite modem, or a modem to provide a data communication connectionto a corresponding type of telephone line. As another example,communication interface 1618 may be a local area network (LAN) card toprovide a data communication connection to a compatible LAN. Wirelesslinks may also be implemented. In any such implementation, communicationinterface 1618 sends and receives electrical, electromagnetic or opticalsignals that carry digital data streams representing various types ofinformation.

Network link 1620 typically provides data communication through one ormore networks to other data devices. For example, network link 1620 mayprovide a connection through local network 1622 to a host computer 1624or to data equipment operated by an Internet Service Provider (ISP)1626. ISP 1626 in turn provides data communication services through theworld wide packet data communication network now commonly referred to asthe “Internet” 1628. Local network 1622 and Internet 1628 both useelectrical, electromagnetic or optical signals that carry digital datastreams. The signals through the various networks and the signals onnetwork link 1620 and through communication interface 1618, which carrythe digital data to and from computer system 1600, are example forms oftransmission media.

Computer system 1600 can send messages and receive data, includingprogram code, through the network(s), network link 1620 andcommunication interface 1618. In the Internet example, a server 1630might transmit a requested code for an application program throughInternet 1628, ISP 1626, local network 1622 and communication interface1618.

The received code may be executed by processor 1604 as it is received,and/or stored in storage device 1610, or other non-volatile storage forlater execution.

11. Equivalents, Extensions, Alternatives and Miscellaneous

In the foregoing specification, possible embodiments of the inventionhave been described with reference to numerous specific details that mayvary from implementation to implementation. Thus, the sole and exclusiveindicator of what is the invention, and is intended by the applicants tobe the invention, is the set of claims that issue from this application,in the specific form in which such claims issue, including anysubsequent correction. Any definitions expressly set forth herein forterms contained in such claims shall govern the meaning of such terms asused in the claims. Hence, no limitation, element, property, feature,advantage or attribute that is not expressly recited in a claim shouldlimit the scope of such claim in any way. The specification and drawingsare, accordingly, to be regarded in an illustrative rather than arestrictive sense.

What is claimed is:
 1. A display system, comprising: one or more lightsources configured to emit first light with a first spectral powerdistribution; one or more light regeneration layers configured to bestimulated by the first light and to convert at least a portion of thefirst light and recycled light into second light, the second lightcomprising (a) primary spectral components that correspond to one ormore primary colors and (b) secondary spectral components that do notcorrespond to the one or more primary colors; and one or more notchfilter layers configured to receive a portion of the second light and tofilter out the secondary spectral components from the portion of thesecond light, wherein the portion of the second light is directed to aviewer of the display system and configured to render images viewable tothe viewer.
 2. The display system as recited in claim 1, wherein thefirst light comprises one or more of: UV spectral components or bluelight spectral components.
 3. The display system as recited in claim 1,wherein the one or more light sources comprises one or more of: laserlight sources, light-emitting diodes (LEDs), or cold cathode fluorescentlights (CCFLs).
 4. The display system as recited in claim 1, wherein atleast one of the light regeneration layers comprises one or more of:quantum dot materials or remote phosphor materials.
 5. The displaysystem as recited in claim 1, further comprising: one or more lightmodulation layers configured to modulate light transmitting throughindividual subpixels in a plurality of subpixels of the display system;one or more color filter layers configured to impart designated primarycolors to the individual subpixels in the plurality of subpixels; andzero or more additional optical stacks.
 6. The display system as recitedin claim 1, wherein at least one of the one or more light sources, atleast one of the one or more light regeneration layers, and at least oneof the one or more notch filter layers form a light unit to the displaysystem.
 7. The display system as recited in claim 1, wherein at leastone of the one or more light regeneration layers and the one or morenotch filter layers do not belong to any light unit to the displaysystem.
 8. The display system as recited in claim 1, wherein the primaryspectral components represent at least two sets of primary colors,wherein each set in the at least two sets of primary colors isconfigured to support a full complement of a primary color system,wherein a plurality of primary spectral components corresponds to aplurality of non-overlapping light wavelength ranges, and wherein eachof the plurality of primary spectral components in the at least two setsof primary colors is in a respective light wavelength range in theplurality of non-overlapping light wavelength ranges.
 9. The displaysystem as recited in claim 1, wherein the display system is configuredto recycle at least a portion of transmissive light comprises one ormore of light originated from the one or more light sources, lightregenerated by the one or more light regeneration layers, or lightreflected by one or more components in the display system.
 10. A displaysystem, at least comprising: one or more light sources configured toemit first light with a first spectral power distribution, wherein thefirst spectral power distribution comprising one or more first spectralcomponents; one or more pass band filter layers configured to pass lightof one or more first wavelength bands represented by the one or morefirst spectral components, and to reflect light of one or more primarycolors, wherein the light of the one or more primary colors compriseswavelengths outside the one or more first wavelength bands; and one ormore light regeneration layers configured to be stimulated by the firstlight as filtered by the one or more pass band filter and to convert atleast a portion of the filtered first light and recycled light intosecond light, the second light comprising primary spectral componentsthat include the one or more primary colors.
 11. The display system asrecited in claim 10, wherein the first light comprises one or more of UVspectral components, or blue light spectral components.
 12. The displaysystem as recited in claim 10, wherein the one or more light sourcescomprises one or more of laser light sources, light-emitting diodes(LEDs), or cold cathode fluorescent lights (CCFLs).
 13. The displaysystem as recited in claim 10, wherein at least one of the lightregeneration layers comprises one or more of quantum dot materials, orremote phosphor materials.
 14. The display system as recited in claim10, further comprising: one or more light modulation layers configuredto modulate light transmitting through individual subpixels in aplurality of subpixels of the display system; one or more color filterlayers configured to impart designated primary colors to the individualsubpixels in the plurality of subpixels; and zero or more additionaloptical stacks.
 15. The display system as recited in claim 10, whereinat least one of the one or more light sources, at least one of the oneor more light regeneration layers, and at least one of the one or morepass band filter layers form a light unit to the display system.
 16. Thedisplay system as recited in claim 10, wherein at least one of the oneor more light regeneration layers and the one or more pass band filterlayers do not belong to any light unit to the display system.
 17. Thedisplay system as recited in claim 10, wherein the primary spectralcomponents represents at least two sets of primary colors, wherein eachset in the at least two sets of primary colors is configured to supporta full complement of a primary color system, wherein a plurality ofprimary spectral components corresponds to a plurality ofnon-overlapping light wavelength ranges, and wherein each of theplurality of primary spectral components in the at least two sets ofprimary colors is in a respective light wavelength range in theplurality of non-overlapping light wavelength ranges.
 18. The displaysystem as recited in claim 10, wherein the second light furthercomprises secondary spectral components that do not correspond to theone or more primary colors, and wherein the display system furthercomprises one or more notch filter layers configured to receive aportion of the second light and to filter out the secondary spectralcomponents from the portion of the second light, wherein the portion ofthe second light is directed to a viewer of the display system andconfigured to render images viewable to the viewer.
 19. A method,comprising: emitting, with one or more light sources, first light with afirst spectral power distribution; stimulating one or more lightregeneration layers with the first light to convert at least a portionof the first light and recycled light into second light, the secondlight comprising (a) primary spectral components that correspond to oneor more primary colors and (b) secondary spectral components that do notcorrespond to the one or more primary colors; and receiving, by one ormore notch filter layers, a portion of the second light, wherein the oneor more notch filter layers filter out the secondary spectral componentsfrom the portion of the second light, wherein the portion of the secondlight is directed to a viewer of a display system and configured torender images viewable to the viewer.
 20. The method as recited in claim19, wherein the first light comprises one or more of UV spectralcomponents, or blue light spectral components.
 21. The method as recitedin claim 19, wherein the one or more light sources comprises one or moreof laser light sources, light-emitting diodes (LEDs), or cold cathodefluorescent lights (CCFLs).
 22. The method as recited in claim 19,wherein at least one of the light regeneration layers comprises one ormore of: quantum dot materials or remote phosphor materials.
 23. Themethod as recited in claim 19, further comprising: modulating, with oneor more light modulation layers, light transmitting through individualsubpixels in a plurality of subpixels of the display system; impartingdesignated primary colors to the individual subpixels in the pluralityof subpixels with one or more color filter layers.
 24. The method asrecited in claim 19, wherein at least one of the one or more lightsources, at least one of the one or more light regeneration layers, andat least one of the one or more notch filter layers form a light unit tothe display system.
 25. The method as recited in claim 19, wherein atleast one of the one or more light regeneration layers and the one ormore notch filter layers do not belong to any light unit to the displaysystem.
 26. The method as recited in claim 19, wherein the primaryspectral components represents at least two sets of primary colors,wherein each set in the at least two sets of primary colors isconfigured to support a full complement of a primary color system,wherein a plurality of primary spectral components corresponds to aplurality of non-overlapping light wavelength ranges, and wherein eachof the plurality of primary spectral components in the at least two setsof primary colors is in a respective light wavelength range in theplurality of non-overlapping light wavelength ranges.
 27. The method asrecited in claim 19, wherein the display system is configured to recycleat least a portion of transmissive light comprises one or more of lightoriginated from the one or more light sources, light regenerated by theone or more light regeneration layers, or light reflected by one or morecomponents in the display system.